How do I modify NPC health?

It seems like a very simple thing, but I just can't find the answer.

In the Source Hammer Editor, how does one change the health of an NPC?

I don't really think there is anything else I can add.

There's two ways to do this:

If you want to change an individual NPC's health, you can use the SetHealth or AddHealth inputs -- hook them up to a logic_auto for it to trigger on map spawn.

If you want to change the health of every NPC of a certain class, there's usually a ConVar associated with it which you can look up on the Valve Developer Wiki. For npc_combine_s (Combine Soldiers) for instance, it's sk_combine_s_health.